Engine code

[gooffeyguy]

V4 works perfectly fine

big boost in mpg getting 31.2mpg on the highway and 23.2 around town..
now that i fixed the battery cable issue


here is the official GM diagnostics for the code.(screening it now)


View attachment 244188 View attachment 244189 View attachment 244190 View attachment 244191 View attachment 244192

We're talking non-hybrids here.... Lol

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[BG1988]

We're talking non-hybrids here.... Lol

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

it still applies.. as it's pretty much the same the only difference is the oil pump is better and i got a 60KW 380volt 3 phase starter, electric power steering rack, and a much more powerful electric A/C it's sooo cold, cold enough to see your breath in the dead of summer with the outdoor temp being 100F

 

[gooffeyguy]

it still applies.. as it's pretty much the same the only difference is the oil pump is better and i got a 60KW 380volt 3 phase starter, electric power steering rack, and a much more powerful electric A/C it's sooo cold, cold enough to see your breath in the dead of summer with the outdoor temp being 100F

Yeah but telling us that it works great and you get such amount of increase in gas mileage does us diddly squat.

Non hybrid rigs only see maybe 1-2mpg more with the system enabled vs disabled.

When I first got my Denali and before I disabled the system, I would watch the DIC to see when and how much it activated. It only activated when letting off the gas and coasting, which the engine is using minimal fuel at that time anyway.

Plus the feel of it activating and de-activating was annoying, but that's probably something hybrid folks are used to, feeling the engine starting up and stopping... Lol

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[BG1988]

Yeah but telling us that it works great and you get such amount of increase in gas mileage does us diddly squat.

Non hybrid rigs only see maybe 1-2mpg more with the system enabled vs disabled.

When I first got my Denali and before I disabled the system, I would watch the DIC to see when and how much it activated. It only activated when letting off the gas and coasting, which the engine is using minimal fuel at that time anyway.

Plus the feel of it activating and de-activating was annoying, but that's probably something hybrid folks are used to, feeling the engine starting up and stopping... Lol

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

um you don't feel anything from the v4 to v8 and back ... or the engine starting mid drive..


that is because your using 87 octane that is why you feel the engine shake it pulls the timing to 0 or negative when in v4 mode with 87 octane when it switch from v8 mode that is why it might get stuck in a loop or rapid switch from v8 to v4 etc..


try 91/93 octane make sure to go to a good station (not shell or acro i got screwed with 87 out of the 91 pump)
like chevron/texaco or mobil/exxon


you have the VVT 6.2L so you can take advantage of it.

I all ready tried 87octane the best I could do was 18.5/18.5 MPG..
Active fuel management disabled or not working or LOOP of death..
the feeling of it activating and de-activating was annoying,


@swathdiver is getting a little over 19mpg on his 5.3 rig with 93 octane fuel..


with Gas prices at record lows
the upgrade to 91/93 octane will be the best thing to do. even if you only gain 2mpg or 3mpg that is a lot of money saved overtime


$413.30 saved over the normal 18.5mpg i would have gotten.

 

[gooffeyguy]

um you don't feel anything from the v4 to v8 and back ... or the engine starting mid drive..


that is because your using 87 octane that is why you feel the engine shake it pulls the timing to 0 or negative when in v4 mode with 87 octane when it switch from v8 mode that is why it might get stuck in a loop or rapid switch from v8 to v4 etc..


try 91/93 octane make sure to go to a good station (not shell or acro i got screwed with 87 out of the 91 pump)
like chevron/texaco or mobil/exxon


you have the VVT 6.2L so you can take advantage of it.

I all ready tried 87octane the best I could do was 18.5/18.5 MPG..
Active fuel management disabled or not working or LOOP of death..
the feeling of it activating and de-activating was annoying,


@swathdiver is getting a little over 19mpg on his 5.3 rig with 93 octane fuel..


with Gas prices at record lows
the upgrade to 91/93 octane will be the best thing to do. even if you only gain 2mpg or 3mpg that is a lot of money saved overtime


$413.30 saved over the normal 18.5mpg i would have gotten.

I always run 93 or E85, nothing less. AFM/DOD seems pointless on my Denali when watching when it actually activates.

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[Idriveaho]

My avg mpg went up when I plugged in the range device. Shit was annoying to hear it go in and out of v4.

 

[BG1988]

I always run 93 or E85, nothing less. AFM/DOD seems pointless on my Denali when watching when it actually activates.

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

it runs the ICE 100% of the time on the freeway i don't think you get AFM at 85MPH? it's only running 1800-1850RPM at 85mph with limited slip rear diff


if it had a brand new HV battery i would be able to get 38mpg or so... but at 12 years old it provably only has 10-15% capacity left.(0.186 to 0.279kwh of 1.86kwh)

 

[13burb]

First off I would like to say thank you for all of the replies. I didn't think I would get this many. I went home last night and did some investigating. I found that the engine has used about a quart of oil in the last 3k miles. Which I know these engines with the cylinder deactivation will naturally use oil but I didn't think that much. I have been looking into the Black Bear tunes but have never had a tune on any of my vehicles. Any pros/cons you can think of on my other wise stock suburban?

 

[OR VietVet]

If you do a tune with them you are going to want to make sure you have no weak links. No old tune related parts. No vacuum leaks. No fuel pump low pressure problems....etc. Make sure the rest of the drivetrain is also up to ***** to handle the performance. Brakes good, suspension good, steering good, tires good, trans and diffs and transfer case all good and have fresh fluids. Others will chime in.

 

[rjdjbd]

@13burb Here is info I found elsewhere:

DTC P3400: Cylinder Deactivation System Performance

Diagnostic Fault Information

Circuit
Short to Ground
Open/High Resistance
Short to Voltage
Signal Performance
Ignition 1 Voltage
P0102, P0443, P3401, P3425, P3441, P3449
P3400, P3401, P3425, P3441, P3449
--
P3400
Cylinder 1 Deactivation Solenoid Control Circuit 1
P0300, P3401
P0300, P3400, P3401
P0300, P3401
P3400
Cylinder 4 Deactivation Solenoid Control Circuit 2
P0300, P3425
P0300, P3400, P3425
P0300, P3425
P3400
Cylinder 6 Deactivation Solenoid Control Circuit 3
P0300, P3441
P0300, P3400, P3441
P0300, P3441
P3400
Cylinder 7 Deactivation Solenoid Control Circuit 4
P0300, P3449
P0300, P3400, P3449
P0300, P3449
P3400
Circuit/System Description

The cylinder deactivation system is used to deactivate 4 cylinders of the engine under light load driving conditions. The engine control module (ECM) commands the cylinder deactivation solenoids ON to deactivate engine cylinders 1, 7, 6, and 4, switching to 4 cylinders or V4 mode. The cylinder deactivation solenoids controls the oil flow to the appropriate valve lifters. The engine operates on 8 cylinders or V8 mode, during engine starting, engine idling, and medium to heavy throttle conditions.
Ignition voltage is supplied directly to the 4 cylinder deactivation solenoids. The engine control module (ECM) controls the 4 cylinder deactivation solenoids by grounding the control circuit with a solid state device called a driver.
The Cylinder Deactivation System Performance diagnostic is a test of the internal mechanical condition of the engine, during operation in V4 mode. The engine control module (ECM) determines the internal mechanical condition of the engine through the actual measured values of the mass airflow (MAF) sensor, the intake manifold absolute pressure (MAP) sensor, and the throttle position sensor. The actual measured values of the 3 sensors are then compared to the calculated values for V4 mode, stored in the ECM. If the measured values are incorrect for V4 mode, the ECM will set DTC P3400, and will return to V8 mode operation.
Conditions for Running the DTC

• DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0119, P0335, and P0336 are not set.
• The engine speed is between 450-6,400 RPM.
• The IAT Sensor parameter is between -7 and +125°C (+19 and +257°F).
• The ECT Sensor parameter is between 70- 125°C (158-257°F).
• Time in V8 mode is greater than 2 seconds.
• Time in V4 mode is greater than 2 seconds.
• This DTC runs continuously within the enabling conditions.
Conditions for Setting the DTC

• The control module detects that the actual measured values from the MAF sensor, MAP sensor, and TP sensor, is not within the range of the calculated values for V4 mode.
• The above condition is met for greater than 100 milliseconds.
Action Taken When the DTC Sets

• DTC P3400 is a Type B DTC.
• The engine will return to V8 mode.
Conditions for Clearing the DTC

DTC P3400 is a Type B DTC.
Diagnostic Aids

• This DTC will not set during engine idling conditions. The vehicle will need to be driven for the DTC to set.
• The valve lifter oil manifold solenoids are assigned to the following engine cylinders:
- Solenoid #1 = Cylinder #1
- Solenoid #2 = Cylinder #4
- Solenoid #3 = Cylinder #6
- Solenoid #4 = Cylinder #7
Reference Information

Schematic Reference

Engine Controls Schematics
Connector End View Reference


• Engine Control Module Connector End Views
• Engine Controls Connector End Views
• Electrical Center Identification Views

Description and Operation

Cylinder Deactivation (Active Fuel Management) System Description
Electrical Information Reference


• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference


• Scan Tool Data List
• Scan Tool Output Controls
• Scan Tool Data Definitions

Special Tools Required

EN-46999 Displacement On Demand Tester
Circuit/System Verification

1. Note: The engine oil level and the oil pressure are critical to the correct operation of the Cylinder Deactivation System. Verify that the engine has the correct oil level and the correct oil pressure before continuing with this diagnostic. Refer to Oil Pressure Diagnosis and Testing. Inspect the Valve Lifter Oil Filter for a restriction or blockage. Refer to Valve Lifter Oil Filter Replacement.


<LI type=1>Ignition ON, observe the scan tool DTC information. Verify that DTC P0201-P0208, P0351-P0358, P3401, P3425, P3441, or P3449 is not set.
⇒If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.




<LI type=1>Engine idling at the normal operating temperature. Verify there is no abnormal engine noise.
⇒If there is an abnormal engine noise, refer to Symptoms - Engine Mechanical for further diagnosis.


<LI type=1>Perform the Cylinder Deactivation (Active Fuel Management) System Compression Test. The Cylinder Deactivation System should pass the compression test.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. <LI type=1>Ignition OFF, remove the valve lifter oil manifold assembly ignition fuse from the underhood fuse block. Note: Probe each terminal at the underhood fuse block with a test lamp connected to ground to determine what terminal to connect the DMM. The test lamp should not illuminate on the circuit that needs to be tested.


<LI type=1>Connect a DMM between the ignition circuit fuse terminal going to the valve lifter oil manifold assembly and the ECM housing. <LI type=1>Ignition ON, command each Cylinder 1, 4, 6, and 7 Deactivation solenoid ON and OFF with the scan tool. Verify the resistance of each solenoid is between 11-18 Ω with the solenoid commanded ON.
⇒If greater than the specified range for all cylinder deactivation solenoids, test the ignition circuit for an open/high resistance.



⇒If greater than the specified range for one or more but not all cylinder deactivation solenoids, test both the control circuit and ignition circuit for an open/high resistance or an open/high resistance in the cylinder deactivation solenoid. If the circuits and solenoid test normal replace the ECM.
2. If all circuits and components test normal, refer to Cylinder Deactivation (Active Fuel Management) Valve Lifter Oil Manifold Diagnosis and Testing for further mechanical diagnosis of valve lifter oil manifold assembly.

Component Testing
Static Test

1. <LI type=1>Ignition OFF, disconnect the harness connector at the valve lifter oil manifold assembly. <LI type=1>Connect the harness that is labeled resistance from the displacement on demand (DOD) tester to the valve lifter oil manifold connector. <LI type=1>Connect the power leads from the DOD tester to B+ and ground. Test for 11-18 Ω on each valve lifter oil manifold solenoid.
⇒If not within the specified range for each solenoid, replace the valve lifter oil manifold assembly.
2. Test for infinite resistance between each valve lifter oil manifold circuit terminal listed and the valve lifter oil manifold housing.
⇒If less than infinite resistance, replace the valve lifter oil manifold assembly.

Dynamic Test

1. <LI type=1>Ignition OFF, disconnect the harness connector at the valve lifter oil manifold assembly. <LI type=1>Connect the cable that is labeled power from the displacement on demand DOD tester to the connector. <LI type=1>Connect the power leads from the DOD tester to B+ and ground.
2. Command each valve lifter oil manifold solenoid ON and OFF using the DOD tester. You should be able to hear each solenoid turn ON and OFF.
⇒If the function does not perform as specified, replace the valve lifter oil manifold assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Valve Lifter Oil Manifold Replacement

• Control Module References for ECM replacement, setup, and programming

Read through all of that twice. Now I wish I was even remotely smart enough to understand any of it! But great info for those that do...